In the production of an optical element such as an organic EL (Electro-Luminescence) element, a method of pattern printing an organic layer such as a luminescent layer in the form of dots by an ink jet (IJ) method, may be employed. In such a method, partition walls are formed along the profiles of dots to be formed, and an ink containing the material for an organic layer is injected into compartments (hereinafter referred to also as opening sections) defined by the partition walls, followed by e.g. drying and/or heating, to form dots in a desired pattern.
In the above method, in order to prevent mixing of the ink between the adjacent dots and in order to uniformly apply the ink in forming the dots, the upper surface of the partition walls is required to have ink repellency, while the opening sections for forming dots as defined by the partition walls including the side surfaces of the partition walls are required to have ink-philicity.
Thus, in order to obtain partition walls having ink repellency on the upper surface, a method has been known to form partition walls corresponding to the pattern of dots by photolithography employing a photosensitive composition containing an ink repellent agent. For example, Patent Document 1 discloses a negative photosensitive resin composition containing a silicone-based ink repellent agent comprising a hydrolyzed condensate of a fluorinated hydrolysable silane compound.
Further, in production of partition walls by photolithography employing a photosensitive resin composition, with a view to improving the productivity, it is necessary to carry out curing of the photosensitive resin composition at a low exposure amount. Particularly if curing of a layer having ink repellency to be formed on the upper surface of the partition walls is insufficient, the layer may be eluted at the time of development and become extremely thin, or the layer itself may disappear in some case, and thus it is important to sufficiently cure such a layer. For example, Patent Document 2 discloses a photosensitive composition employing a specific photopolymerization initiator. As a sensitizer, a monofunctional or bifunctional thiol compound is disclosed.